The load upon a railroad vehicle wheel or applied thereby to a track has been measured heretofore by special equipment mounted below the vehicle and having a number of devices corresponding to the number of wheels of the railroad car. Such equipment is expensive and occupies considerable space and is not adaptable for use with vehicles having different wheel bases.
In another system, a hydraulic device provided with a pressure gauge is located beneath the axle box of the vehicle and is operated to lift the vehicle wheels from the track. The gauge, responsive to hydraulic pressure, can read the load which can then be calculated in terms of the loads on the opposite wheels of a given axle to provide the measurement. This system has been found to be subject to low sensitivity and error and has the disadvantage that rigid supports must be provided under the axle boxes under the vehicle.